Going further: could wars be started because of something someone made in a video game engine?
A video + a testimony "This is what I saw on that fateful night" or "I retreived this video from the officer's body cam immediately after the incident, it was in the custody the whole time and forensic analysis shows no sign of tampering" carries an entirely different weight than that video alone.
Regarding wars, in the recent conflicts we already have cases where doctored photo & video evidence was used as arguments and vice versa, where real evidence is dismissed because it can be made synthetically - and it obviously can, they become evidence only if you[r organization] gathered it yourself or you really trust the soruce.
Wars definitely won't be started because of something made in a video game, but such videos can and most likely will be used in justifying a war decision to the global public and building the relevant PR/propaganda materials.
in my opinion, this doesn't change much.